Method of treating hides before tanning.



the King of Great Britain, residing to prevent the formation of-salt stains and possible to prevent a hides and we have succeeded in elucidating water and salts containing water of crystal- UNITED STATES PATENT OFFICE.

CHARLES cma'oN moons AND WILLIAM TRANTOM, or LYMM, ENGLAND.

' METHOD or TREATING HIDES BEFORE TANNING.

Patented Mai'.24,1914. Serial No. 303,025.

Specification of Letters Patent.

.No Drawing. Application filed November 25, 1913.

lizationinstead of by the addition of antiseptics. It is well known that ordinary com- To all whom it may concern I ,Be it known that'we, CHARLES CLIFTON Moonn and VVJLIJAM TRAN'roM, subjects of at Lymm, in the county of Chester, in the Kingdom of England, have invented certain new and useful Improvements in the Method of Treating Hides Before Tanning, of which the following is a specification.

The object of the present invention isan improved process for the treatment of hides immediately after removal from the carcass and before tanning in order to prevent decomposition and consequent loss of hide substance. Such hides are frequently sprinkled with commercial sodium chlorid and it is found that stains are frequently produced after such treatment. Moreover it is known that when the salt is subsequently washed out, a certain loss of hide substance takes place. Some experimenters have endeavored to prevent the formation of salt stains by the addition of an antiseptic such as zinc chlorid or mustard oil since these stains were considered to be due to the action of bacteria, though certain observers suggested that they arose from the hemoglobin of the blood. Others have suggested the addition of borax which apparently prevents stains but causes a slight general blue coloration of the whole mass. Where borax or more powerful antiseptics, such as sodium fluorid, mustard oil, etc., are employed however there is still the loss in hide substance when the salt is washed out.

It is the object of the of such salts especially sod um sulfate and considerably apart rom the salt stains. have found that th' to the avoidance of the ormation of difficultly soluble calcium and magnesium compounds with the albuminoid matter of the hide colloid and also to the avoidance of the formation of insoluble soaps with the fatty matter contained in and adhering to the hide.

remove substantially all the impurities from commercial common salt process disclosed inthe specification of British Patent No. 23642/02, granted to us which succeeds in producing a product containing 99.99% ofsodium chlorid. We then treat the hide immediately after removal from the carcass with about 15 to 20% by present invention to these disadvantages and mc'ire particularlv in hide substance. pointed out that if it is lossbf from 2 to 4% of hide substance, the process would be of great commercial importance since it would weight of such chem cally pure salt in the yield an actually greater weight of better dry and very-finely divided product. We have accordingly made ex- "11 this condition is readily tensive experiments during both winter and hide. The weight of an summer months with large quantities of about to '65 lbs. and

chemically pure salt to be used for a hide this weight is about 10 to 12 lbs. The hide as removed from the carcass is s read out on the floor with the hair side own and the quantity of chemically pure tionedjs sprinkled evenly over the flesh side of the ,hide. The salt is dissolved in the to diminish the loss It need scarcely be taken up by the ordinary hide is the causes which underlie both the above mentioned phenomena. We willdiscuss this matter more fully laterbut we may say here that we have discovered that staining can be prevented if bacteriological decomposition ls inhibited simply by the exclusion ofv mercial salt contains considerable quantities i imfprovement is due form. The salt natural moisture of the hide and being perpreferably by the the quantity of 1 salt menfectly pure, no impurities or water, either mechanically or chemically combined are introduced into the hide. The result of this treatment is that bacteriological decomposition is immediately stopped or suspende for an indefinite period, thereby keeping the hide in a perfectly fresh eonditionwithout decomposition or appreciable loss of hide substance. With this method of treatment the hide can be kept indefinitely. \Vh'en the hide is to be tanned it is thoroughly washed with pure water but it is not necessary that this washing should remove all the salt, as is the case when impure salt is used, as, even if a small quantity of the chemically pure sodium chlorid is left in the hide substance, it'will not enter into any objectionable chemical reaction or exert any prejudicial effect upon the subsequent tanning process. After undergoing this process of treat ment with chemically pure sodium chlorid the hide is left in a very active form and we find that it is rendered more capable of reacting with the tanning material.

We may sum up our process by saying that in so far as the salt stains are concerned, we treat the hides aseptically as compared to the processes using mustard oil or zine chlorid which are antiseptic or the process using commercial common salt which 1s sept1c, s1nce in this latter case considerable quantities of water are introduced into the hide setting up bacteriological decomposition. Moreover owing to the absence of hygroscopic impurities especially magnesium chlorid we are enabled to avoid the addition of water since sodium chlorid itself contains no water of crystallization. By the exclusion of the mineral impurities and also of water, we further find that it is possible to save from 2 to 4% by weight of hide substance.

We declare that what we claim is 1. The process of preserving hides before tanning which comprises treating said hides after removal from the carcass with chemically pure sodium chlorid.

2. The process of preserving hides before tanning which comprises treating said hides after removal from the carcass with very finely divided chemically pure sodium chlorid. p

3. The process of preserving hides before tanning which comprises treating said hides after removal from the carcass with dry chemically pure sodium chlorid.

4. The process of preserving hides before tanning which comprises treating said hides after removal from the carcass with sodium chlorid substantially free from calcium and magnesium salts and salts containing water of crystallization.

In witness whereof, we have hereunto signed our names this 15 day of Novr. 1913, in the presence of two subscribing Witnesses.

CHARLES CLIFTON MOORE. WM. TRANTOM..

Witnesses:

HAROLD EDWIN Porrs, RICHARD MERCER. 

